Facebook’s Slingshot does take a slightly different approach since you’ll need to reply with a photo before you can see what was sent to you. That should increase engagement, but only time will tell how well it’ll be received.
Because you have to respond to a shot before you can see it, these notifications act as nags instead of notifiers. If you tap on a new notification, “Shot from Adam,” you won’t be able to view it — until you send a shot of what you’re doing back to Adam. Thus, shots feel less urgent than messages, since there’s no expectation that you’ll be able to open them immediately. The app feels far more like a News Feed with push notifications than anything else — except this News Feed requires you to share a post before you can view it, so there’s no place for lurkers. The Verge